1. Field of the Invention
The present invention relates to a mounting method of an electronic component, an electronic component mount body and a manufacturing method thereof, and particularly, to a mounting method of an electronic component, an electronic component mount body and a manufacturing method thereof, wherein the electronic component is mounted on a mount board by flip-chip bonding.
2. Description of the Related Art
In semiconductor mount fields, at the time an electronic component is mounted on a mount board, electrical connection between a component terminal of the electrical component and a board terminal of the mount board is generally performed by a wire bonding system or a flip-chip system. The electronic component is, for example, an integrated circuit (IC). Examples of the mount board include a lead terminal of a semiconductor package represented by a quad flat package (QFP), a chip size package (CSP) or the like, or a print board represented by a chip on board (COB) or the like.
In the flip-chip system, each of the component terminal and the board terminal has a material and a shape suitable for the electrical bond. At the time the electronic component is mounted on the mount board by the flip-chip system, after positional alignment of the component terminal and the board terminal is performed, pressures, vibrations, heat or the like is applied thereto. Thereby the component terminal and the board terminal are electrically bonded (for example, see Japanese Patent Application Publication No. 2006-128484)
FIG. 8 is a schematic plan view and side view or explaining a component terminal. An example of a component terminal 101 used in the flip-chip system includes a stud bump. The component terminal 101 is arranged on a component electrode 103 of the electronic component. The component electrode 103 is, for example, a pad of a semiconductor chip. The component terminal 101 formed of the stud bump has a tip end formed in a sharp shape due to the formation method.
FIGS. 9A to 9D are view for explaining the process in which the component terminal and the board terminal are bonded.
As shown in FIG. 9A, the component terminal 101 is arranged to direct the tip end to a side of a board terminal 105. The board terminal 105 is provided with an inclined portion 107 on the surface, which is the wider as closer to the base end side toward a peripheral edge. The board terminal 105 is arranged on a board electrode 109. The board electrode 109 is, for example, a lead terminal of a semiconductor package or a connection land of a print board.
The component terminal 101 and the board terminal 105 are arranged to be positioned in center to each other. At this time, there are some cases where a positional deviation occurs between the center of the component terminal 101 and the center of the board terminal 105. This positional deviation is caused by, for example, positioning accuracy between the component terminal 101 and the board terminal 105, positional accuracy of the component terminal 101 on the component electrode 103, positional accuracy of the board terminal 105 on the board electrode 109 or the like. This positional deviation amount is usually the degree of several μm to 10 μm (micrometers).
After the positioning between the component terminal 101 and the board terminal 105 is performed, as shown in FIG. 9B the component terminal 101 relatively approaches the board terminal 105. The tip end of the component terminal 101 makes contact with the inclined portion 107 of the board terminal 105.
As the bonding operation proceeds, the component terminal 101 further relatively approaches the board terminal 105. As shown in FIG. 9C, the tip end portion of the component terminal 101 moves to a peripheral edge side of the board terminal 105 along the inclined portion 107 of the board terminal 105 to increase the positional deviation amount. As the bonding operation further proceeds, the positional deviation amount increases.
At the completion of the bonding operation, as shown in FIG. 9D, the positional deviation amount between the center of the component terminal 101 and the center of the board terminal 105 is several times to several ten times the amount at the time the component terminal and the board terminal are positioned. The positional deviation of the component terminal 101 from the board terminal 105 leads to a positional deviation of the electronic component from a mount position of the electronic component on the mount board.
When a portion of the board terminal 105 with which the component terminal 101 makes contact is flat, this positional deviation is reduced. However, in almost all of a plated layer, a Cu pillar bump, a solder ball and the like representative of the board terminal 105, the portion with which the component terminal 101 makes contact is not formed to be flat, and is more or less inclined. Therefore in fact, there are many cases where the sharp tip end portion of the component terminal 101 is crushed to be flat (leveling) before flip-chip mounting to reduce the causes of the positional deviation, thus improving mounting properties.
FIG. 10 is schematic side views for explaining a flattening process of the tip end portion of the stud bump.
A jig 111 a tip end of which is flat strikes the tip end of the component terminal 101 formed of the stud bump. Thereby the tip end portion of the component terminal 101 is flattened.
However, even in the component terminal 101 having the flat tip end portion, if the portion of the board terminal 105 with which the component terminal 101 makes contact is inclined, the above positional deviation possibly occurs.
In view of the above, there exists a need for a mounting method of an electronic component that overcomes the foregoing problems in the conventional technology. The present invention addresses this need in the conventional technology as well as other needs, which will become apparent from those skilled in the art from this disclosure.